What does the offset 20 signify in the below code?
using ModelingToolkit
@variables x y z
@parameters a b c
----Define a nonlinear system
eqs = [0 ~ - y - (z+20),
0 ~ x + a * y,
0 ~ b + (z+20) * (x - c)]
ns = NonlinearSystem(eqs, [x,y,z], [a,b,c])
nlsys_func = generate_function(ns)[2] # second is the inplace version
rossler = ModelingToolkit.eval(nlsys_func)
du = zeros(3); u = ones(3)
params = (0.2,0.2,5.7)
j_func2 = generate_jacobian(ns)[2] # second is in-place
j2! = ModelingToolkit.eval(j_func2)
using NLsolve
nlsolve((out, x) → rossler(out, x, params), (out, x) → j2!(out, x, params), ones(3))
out:
Results of Nonlinear Solver Algorithm
- Algorithm: Trust-region with dogleg and autoscaling
- Starting Point: [1.0, 1.0, 1.0]
- Zero: [0.007026204834100122, -0.035131024170500603, -19.9648689758295]
- Inf-norm of residuals: 0.000000
- Iterations: 8
- Convergence: true
- |x - x’| < 0.0e+00: false
- |f(x)| < 1.0e-08: true
- Function Calls (f): 9
- Jacobian Calls (df/dx): 9